Due to the ever increasing use of engine driven equipment, such as generator sets, environmental concerns are forcing the noise emitted from such equipment to be lower and lower. These generator sets are often used in areas where low noise is a requirement. Such uses include construction sites within residential areas, carnivals and movie sets. Thus, the market for sound suppression enclosures is increasing, and the premium charged for such enclosures is currently quite high. For example, the cost of some low noise enclosures is approximately equal to the cost of the engine and generator packages without an enclosure.
An example of an enclosure is disclosed in U.S. Pat. No. 3,462,949 issued to Howard R. Anderson, et al. on Aug. 26, 1969. An enclosure for a gas turbine engine is comprised of a silencer for the engine's compressor and a specially configured compressor inlet housing to provide uniform flow free of turbulence or separation. The enclosure is comprised of an inlet duct means for turning the incoming air through a plurality of right-angle bends, thus silencing any compressor noise.
Another example of an existing enclosure is disclosed in U.S. Pat. No. 4,071,009 issued to Jack H. Kraina on Jan. 31, 1978. The enclosure is mounted around the engine and is comprised of an outer enclosure having a horizontally disposed hood and side walls. An inner enclosure is disposed within the outer enclosure and has a horizontally disposed upper wall spaced vertically between the top of the engine and the hood to define first and second airflow passages therewith. An airflow guide means is secured internally on each of the sidewalls to define a passage therebetween which communicates with the second airflow passage. The hood, sidewalls and upper and forward walls of the inner enclosure each have a layer of sound absorbing material secured thereon.
An example of an existing enclosure is disclosed in U.S. Pat. No. Re. 29,923 issued to Gerhard Thien, et al. on Mar. 6, 1979. The soundproof casing is divided by at least one partition wall into two cooling air ducts separated from each other. One of the ducts contains all fuel carrying members of the engine, and the second duct contains the exhaust system of the engine.
The noise reduction enclosure defined herein reduces the noise emitted from engine driven equipment and provides noise reduction enclosure at an economical cost to the customer.